Fire-Inhibiting Nonflammable Gel Polymer Electrolyte for Lithium-Ion Batteries

Herein, we present a gel polymer electrolyte (GPE) improving nonflammability of lithium-ion batteries (LIBs) by blocking radical-initiated chain reactions which cause thermal runaway and finally fire issues. The polymer that makes up the nonflammable GPE was (1) soluble in carbonate electrolytes, (2) cross-linkable in the presence of a popularly used lithium salt such as LiPF₆, (3) gelated only with 2 wt % in electrolytes, and (4) radical-scavenging by its functional side chains. Electrolytes having the polymer were thermally gelated within battery cells after the cells were assembled by a conventional way. LIB cells with the GPE were durable against external thermal and mechanical shocks without sacrificing cell performances. The high transference number of lithium ions and liquid-equivalent ionic conductivity of the GPE at only 2% solid content having a stable solid-electrolyte interphase layer formed even improved cell performances at normal operation conditions.